13 November 2018
Greater Wellington Regional Council, along with lead researchers from NIWA, is trialling a new way of monitoring water
quality in Porirua streams. The method is expected to provide a deeper understanding of where contaminants are coming
from and gauge how bad water quality can get during a rain event.
Members of Greater Wellington’s Marine and Freshwater team have placed a series of new passive sampling devices in local
streams. The devices include stormwater bottles, which capture water samples when the streams rise to a pre-determined
level, and small gel discs that are able to take up dissolved metals. The resulting water samples collected are sent to
Hills Lab in Hamilton.
‘We are one of the first regional councils in the country to trial these devices to see if they can be used for routine
monitoring programmes,” says Senior Environmental Scientist, Dr Claire Conwell.
“Previously we had to send staff out after heavy rain, sometimes losing precious time in capturing the ‘first flush’,
which is when contaminants first get washed into the streams.”
Dr Conwell says that the new method has the added advantage of being cheap to set up and maintain. “It will enable us to
hone in on areas of concern, and help us to identify where contaminants are coming from. We will also be able to
cross-check the samples against the routine monitoring we carry out, to ensure this methodology is hitting the mark.”
So far the devices have been installed in Porirua only but may be introduced at other sites in the Wellington region if
the trial is successful. The project has been funded through a Ministry for Business and Innovation Envirolink grant.